Pop-up auto-shutoff indicator for electric pressing irons

ABSTRACT

A pop-up auto-shutoff indicator for a pressing iron includes a signal-activated pop-up switch adapted to provide power to a soleplate heater when the pop-up switch is depressed by the user. An auto-shutoff circuit is adapted to receive an input signal from a motion detector and provide an actuation signal to actuate the pop-up switch upon detecting no motion of the iron for a predetermined period of time and to disconnect power to the soleplate heater.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

This disclosure relates to an electromechanical pop-up indicator for a household pressing iron that provides a visual and audible signal to the user when power has been cut off to the soleplate.

2. Description of the Related Art

It is known in the art of pressing irons to provide an indicator that warns the user that the heated soleplate of the iron is still hot, such as is described in Rius et al., U.S. Pat. No. 6,548,785 B1, issued Apr. 15, 2003, for a PRESSING IRON WITH RESIDUAL HEAT WARNING DEVICE.

It is also known to provide irons with thermostats and various shut-off devices to prevent overheating of the soleplate. It is further known to use an integrated timer circuit to automatically shut off a pressing iron, as is disclosed in commonly assigned patent Contri, U.S. Pat. No. 4,661,685, issued Apr. 28, 1987, for an ELECTRIC PRESSING IRON.

However, a problem can arise when the user is not continually present to monitor any indicator. One problem arises when the user leaves the iron on the fabric and then is distracted so as to move away from the appliance. Another problem arises when the user stands the iron upright on its heel with its soleplate in a vertical plane, walks away, and the iron tips over back onto the fabric without the user's knowledge. This can result in a scorched fabric. It is desirable to provide an iron with a mechanism that automatically shuts off the iron when no movement of the iron has been detected for a predetermined period of time. It is also desirable to provide some indication to the user that such an “auto-shutoff” has occurred so that the user does not incorrectly assume that the iron has malfunctioned. Moreover, a need exists for a positive mechanical indication that power to the iron has been disconnected, as prior electric indicators, such as red lights, often confused the user by suggesting to the user that the iron was still “on” when in fact power to the soleplate heater was shut off.

BRIEF SUMMARY OF THE DISCLOSURE

A pop-up auto-shutoff indicator for a pressing iron includes a signal-activated pop-up switch adapted to provide power to an iron soleplate heater when depressed by the user, a motion sensor, and an auto-shutoff circuit adapted to receive input from the motion detector and provide a signal to activate the pop-up switch upon detecting no motion of the iron for a predetermined period of time and disconnecting power to the soleplate.

Another aspect of the invention includes an attitude detector providing a signal to an auto-shutoff circuit which is adapted to activate the pop-up switch if the iron lies flat without movement for a first predetermined period of time.

In another aspect of the invention the first predetermined period of time is from about thirty to about sixty seconds.

Another aspect of the invention further includes an attitude detector providing a signal to an auto-shutoff circuit which is adapted to activate the pop-up switch if the iron is upright on its heel without movement for a second predetermined period of time.

In another aspect of the invention the second predetermined period of time is from about fifteen minutes to about thirty minutes.

Another aspect of the invention further comprises a lamp or other light source such as a light-emitting diode indicating when power is being supplied to the soleplate heater.

In another aspect of the invention the lamp is integrated into the pop-up switch to provide a visual indication to a user that the iron is on if illuminated or off if not illuminated.

In another aspect of the invention the auto-shutoff circuit includes a timer.

In another aspect of the invention the timer automatically resets itself upon a change in the output of the motion sensor.

In another aspect of the invention the motion sensor comprises a mercury switch.

In another aspect of the invention the motion sensor comprises a rolling ball switch.

In another aspect of the invention the motion sensor comprises an inductive rolling ball switch.

Disclosed is a pop-up auto-shutoff indicator for a pressing iron, including a signal-activated pop-up switch adapted to provide power to a soleplate heater when depressed by the user, a motion sensor for detecting movement of the iron, and an auto-shutoff circuit for receiving input from the motion detector and providing a signal to activate the pop-up switch upon detecting no motion of the iron for a predetermined period of time and disconnecting power to the soleplate.

Also disclosed is a pop-up auto-shutoff indicator for a pressing iron, including a signal-activated pop-up switch adapted to provide power to a soleplate heater and to one or more DC power supplies when depressed by the user. A pop-up switch signaling device is adapted to signal the pop-up switch. An interface controls a controller for the signaling device, so as to enable the controller to activate the pop-up switch and disconnect power to the soleplate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial top plan view of a pressing iron of the invention.

FIG. 2 is a circuit diagram of an embodiment of the invention.

FIG. 3 is a circuit diagram of an embodiment of a circuit adapted for use with an existing auto-off iron as a retrofit.

FIGS. 4 a and 4 b are side views of an embodiment of an iron of the invention showing the pop-up switch in the depressed and “popped-up” positions, respectively.

FIG. 5 is an exploded view of one embodiment of a pop-up switch constructed in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1 there is shown a top view of an iron 1 having a heated soleplate 5 and a handle 2. Various user controls may typically be provided, such as a temperature control dial 4 and control buttons 3 for providing steam blasts and water spray. A steam control 8 is also often provided to control the amount of steam delivered. In the embodiment shown, a pop-up switch 10 is provided which may include an integrated power indicator lamp 11. Alternatively, a separate power indicator lamp 6 may be provided. Either lamp can be in the form of a color-changing LED which changes color to indicate the iron has reached a desired ironing temperature.

The pop-up switch 10 is of the normally open variety, meaning that power is not supplied to the soleplate heater until the pop-up switch 10 is depressed by the user (see FIG. 4 a). The term “pop-up” is meant to include a mechanical movement of a mechanical member such as a button, slide switch, lever, or the like, and which movement can be seen by a user as a physical indicator of the state of the iron, such as “ON” or “OFF.”

When depressed, the pop-up switch 10 remains in the down position until one of two events occurs, either (1) the user depresses the pop-up switch again, or (2) the pop-up switch is activated by an electronic signal to “pop” back up (see FIG. 4 b), thereby shutting off power to the soleplate heater. Such pop-up type switches are commercially available and typically operate under the action of a small solenoid. When power is applied to the solenoid (typically 12 to 24 volts), the pop-up switch 10 latches in the down position with the circuit in the closed position thereby applying power to the soleplate heater.

The operation of the pop-up auto-shutoff indicator is as follows. When the user depresses the pop-up switch 10, as shown in FIG. 4 a, power is supplied to the soleplate 5 in accordance with the temperature control 4 setting. An auto-shutoff circuit, such as disclosed in U.S. Pat. No. 4,661,685 noted above, monitors a motion detector and an attitude detector, as more fully explained below, and automatically shuts off power to the soleplate 5 if the user leaves the iron unattended for a predetermined period of time.

Typically, the auto-shutoff is designed to occur within thirty to sixty seconds if the iron is left flat (i.e., in the ironing position) and within fifteen to thirty minutes if left upright on its heel without any motion detected. In such cases, the auto-shutoff circuit will de-activate the pop-up switch, such as by de-activating a solenoid, causing the switch to “pop up” or actuate back into the open circuit position, as shown in FIG. 1 a, thereby shutting off power to the soleplate. The power lamp also goes off when the pop-up switch 10 is de-activated. The pop-up switch will preferably make a clearly audible “click” or other audible signal when this occurs so the user can hear it and thereby confirm that power to the soleplate has been interrupted.

The motion and attitude detectors may be one and the same, as in a mercury or ball-activated switch. A mercury switch typically includes a quantity of mercury within a tube having a plurality of electrical contacts disposed therein to indicate or determine the position of the quantity of mercury. The position of the mercury pool or drop within the mercury switch gives an indication of the attitude of the iron. If the signal from the mercury switch is constant, this indicates that the mercury is not sloshing or moving about and therefore the iron is motionless.

The result of the operation of the invention is that, when the user returns to the iron, the user will see clearly that an auto-shutoff has occurred, rather than thinking something might be wrong with the iron. The user need simply depress the pop-up button again to restore power to the soleplate. The pop-up switch 10 provides a mechanical movement in combination with a light indicator and optional audible signal to provide a user with a clear, unmistakable indication that the iron is on or off.

Referring to FIG. 2, there is shown a circuit diagram of an embodiment of the invention. Here, the pop-up switch 10 is a double-throw single-pole type switch that controls the flow of AC power to the circuit from AC input L and the flow of AC power from AC input N to the soleplate heating element R3. Also provided is a timer 20, which in the embodiment shown is an XM105 Automatic Timer Circuit sold by Xiamen Linktron Microelectronics Company of Xiamen, China. Pin 1 of the timer 20 is ground and is simply connected to the “N” AC input.

Pin 5 is provided with five volts DC to power the timer 20. A 5 volt DC supply is provided by rectifying the “L” AC input line through diode D1 and providing a high power resistor R1 to allow the voltage to be clamped down to five volts by Zener diode ZD1. A small capacitor C5 eliminates noise, while electrolytic capacitor C1 smoothes out the half-waveform into a steady DC supply.

It is also necessary to provide the timer 20 with an AC signal so as to enable it to run it's internal clock. This is achieved by tapping off the “L” AC input through large resistor R2, coupled to the “N” AC input through capacitor C6 and connecting the output to pin 8 of the timer 20.

It is also preferable to have a power indicator lamp 6, which may be a neon lamp NE1 powered by tapping off the direct current halfwave provided by diode D1.

The operation of the XM105 timer 20 is as follows. When the input on pin 4 changes, either from LO (ground) to HI (5 V.) or from HI to LO, the timer 20 resets and begins timing. If pin 4 is HI, the timer will trigger in about thirty seconds. If pin 4 is LO, the timer will trigger in about fifteen minutes. At start-up, the timer output at pin 7 is HI. When the timer triggers, pin 7 is brought LO. By inverting the output of this pin, it is possible to activate power transistor Q1 so as to energize coil L2 and cause the pop-up switch 10 to mechanically release so as to pop up and shut off the iron. There is a second way to achieve this result. Pin 6 is provided by the manufacturer to activate a light emitting diode (LED), which means it is LO at start-up and then begins pulsing when the timer 20 triggers, so as to provide a flashing LED display. It is more convenient to simply use this output to activate the SCR or power transistor Q1. The LED can be mounted directly on the pop-up switch 10 as a lighted cover 11, or as a separate light source 6 mounted, for example, on the top of iron 1. Of course, any other suitable light source may be used in place of a LED.

Pin 3 provides an oscillating signal for powering a buzzer and so is not used here.

Pin 2 is coupled to the AC supply through a capacitor C3 so as to provide a signal used by the timer to provide the buzzer and LED output signals at pins 3 and 6, respectively.

It can be seen that, to operate the pop-up switch 10, an attitude detector 15 is provided that outputs HI when the iron lies flat and LO when the iron is upright. This output is provided to pin 4. So long as the user doesn't cause the output the change by moving the iron, the iron will automatically shut off after thirty seconds if lying flat and after fifteen minutes if upright on its heel with its soleplate aligned substantially upwardly. However, the attitude detector 15 must also act as a motion detector to detect that the user is stroking back and forth over the fabric being ironed when in the flat position.

This may be accomplished using a mercury switch or a rolling ball switch. A mercury switch includes a pool of mercury in a tube having a pair of electrodes. When the mercury makes contact with the electrodes, the circuit is closed. A rolling ball switch works on the exact same principal, but employs a conductive metal ball which rolls inside a tube. Rolling ball switches are somewhat more expensive, but less likely to break and do not present the environmental hazard of possible mercury release. These switches act as both attitude and motion detectors. By stroking the iron over a fabric, the user causes the mercury to flow, or the ball to roll, back and forth, thereby repeatedly opening and closing the switch. Because the XM105 timer 20 rests whenever the input to its pin 4 changes, the timer never triggers so long as this motion continues.

Another solution is to use an inductive rolling ball switch L1 as shown in FIG. 2. An inductive rolling ball switch is a metal ball bearing within a tube, but with no electrodes. Instead, an inductive winding is wrapped around one end of the tube. The ball bearing is of a ferrous metal so that, when it rolls to the end of the tube having the winding, it will be positioned within the winding and thereby significantly alter its inductance. When placed in parallel with a capacitor C4, an LC filter circuit is formed. For the 222 uF capacitor C4 shown, a suitable inductive rolling ball switch is the model BCH180-H sold by Bai Chuan He Electronic Company, China. When the ball is moved outside of the winding, the BCH180-H switch has an inductance of about 180 uH. This goes up to about 235 uH when the ball rolls into the winding.

The inductive rolling ball switch 15 is positioned within the handle of the iron so as to position the ball within the winding when the iron is upright. This causes the AC signal from AC input line to be filtered out, resulting in a LO at pin 4. This arrangement is possible because pin 4 of the XM105 switch is designed to accept oscillating as well as DC input. In general, the values of L1 and C4 are selected to provide a peak-to-peak voltage of from 1.5 Vpp to 5 Vpp when the ball is outside the winding.

FIG. 3 shows a representative retrofit embodiment of the invention. This circuit may be used as the power supply on an iron design already equipped with a motion/attitude detector 15 and controller, such as a timer or microcontroller. Existing designs already on the market may thereby be modified to take advantage of the benefits of the invention.

As in FIG. 2, the AC supply is run through the pop-up switch 10 to supply power to the soleplate heating element R13 and the rest of the circuit. A varistor V1 is provided to protect the circuit. When the pop-up switch 10 is closed, the “N” AC line connects directly to the heating element R13 while the “L” AC line is filtered through C7, R6, and R7 to the bridge rectifier formed by diodes D5, D6, D7, and D8. The output from the bridge rectifier is clamped down to 24 volts by Zener diode ZD2 and the output smoothed out with electrolytic capacitor C8. This provides a 24 volt DC power supply. The 24 volt DC source is divided down by resistor R12, clamped to 5 volts by Zener diode ZD3, and smoothed out by electrolytic capacitor C9. This provides the 5 volt DC power supply.

The pop-up switch 10 is controlled by transistor Q2. The circuit is integrated into the iron via a connector J1 wherein the important lines are made available, namely the 5 V. supply, a ground, the line controlling the transistor Q2 and an AC line tapping off the “L” AC input through a large resistor R10. The AC line is provided because most timers and microcontrollers require the AC signal for internal timing. A fifth pin may be added to the junction for the 24 V. (or 12V.) line, if desired.

As can be seen, an iron design that already has a motion/attitude sensor may be relatively easily connected to this circuit and configured to output a signal to transistor Q2 when it is desired to activate the pop-up switch solenoid and shut the system down.

Referring to FIG. 5, there is shown an exploded perspective view of a commercially available pop-up switch. Within a casing 30 is mounted a plurality of wire posts 31 that protrude outside the casing 30. The drawing shows two pairs of wire posts 31 so as to provide a double pole type switch. A pair of conducting contacts 32 is provided that are each resiliently connected to a slider 34 by a contact spring 33. Lead wires 32′ connect the pop-up switch to the circuits of FIGS. 2 and 3.

Depending upward from the slider 34 is the pop-up switch button 10 b. The slider 34 is resiliently held away from the wire posts 31 by a main spring 35. When the pop-up switch button 10 b is depressed, the slider is depressed to bring the conducting contacts 32 in electrical contact with the wire posts 31, thereby creating a pair of closed electrical contacts (designated as “S1” in FIG. 2 and “S2” in FIG. 3). The contact springs 33 place positive pressure on the conducting contacts 32 against the wire posts 31 to ensure reliable electrical contact.

When the pop-up switch button 10 b and integral slider 34 are depressed, a springloaded cam block 36 engages the slider 34 to hold it in place and keep the conducting contacts 32 in electrical contact with the wire posts 31. The pop-up switch button 10b thereby remains depressed. The cam block 36 is held in engagement with the slider 34 by a sliding iron core element 37 slideably mounted within a bobbin 38 of a solenoid coil and resiliently pushed against the cam block 36 by a cam spring 39. The cam spring 39 may be held in place on a shoulder of the core element within and the bobbin by a spring mount 40. The cam spring 39 may be of a ferrous material so as to enhance the strength of the magnetic field within the bobbin 38. Around the bobbin is a solenoid coil 41 (designated “L2” in FIG. 2 and “L3” in FIG. 3) that provides a magnetic field upon application of a current through its leads 42. When activated, the solenoid coil 41 causes the sliding iron core element 37 to pull the cam 36 away from and out of engagement with the slider 34, thereby causing the pop-up switch 10 to “pop-up” and break electrical contact between the wire posts 31.

The bobbin 38 may be held in place by a bobbin yoke 43 that fits to the casing 30. Alternatively, the bobbin yoke 43 may be integrally molded to the casing 30. The entire assembly is capped off and sealed by a cover piece 44.

The cam block 36 will preferably engage the slider 34 in a manner that allows the user to manually cause the switch to “pop-up.” In other words, should the user wish to shut the system off manually, the user may depress the button again, causing it to return to the open circuit position. The cam block 36, engaged with an appropriately configured mating slider 34, is a means of achieving this, resulting in a pushbutton switch that behaves similarly to the push button on a ball point pen.

The use of a “pop-up” switch is but one embodiment. The teachings of the invention may encompass any mechanical indicator, such as a lever or rotating knob or such, so long as the electromechanical switch has a physically moveable member, visible to the user, that may be moved from an open circuit position to a closed circuit position by the user and then moved back to the open circuit position upon activation.

While various values, scalar and otherwise, may be disclosed herein, it is to be understood that these are not exact values, but rather to be interpreted as “about” such values, unless explicitly stated otherwise. Further, the use of a modifier such as “about” or “approximately” in this specification with respect to any value is not to imply that the absence of such a modifier with respect to another value indicated the latter to be exact.

Changes and modifications can be made by those skilled in the art to the embodiments as disclosed herein and such examples, illustrations, and theories are for explanatory purposes and are not intended to limit the scope of the claims. Further, the abstract of this disclosure is provided for the sole purpose of complying with the rules requiring an abstract so as to allow a searcher or other reader to quickly ascertain the subject matter of the disclosures contained herein and is submitted with the express understanding that it will not be used to interpret or to limit the scope or the meaning of the claims. 

1. An apparatus for a pressing iron having a soleplate and a soleplate heater, comprising: a signal-activated user-visible switch adapted to provide power to the soleplate heater when actuated by a user; a motion detector adapted to provide an input signal; and an auto-shutoff circuit adapted to receive the input signal from the motion detector and to provide an actuation signal to move the switch upon detecting no motion of the iron for a predetermined period of time so as to interrupt power to the soleplate heater and provide a visible mechanical indication of power interruption to the soleplate heater.
 2. The apparatus of claim 1 further comprising an attitude detector and wherein the auto-shutoff circuit is adapted to actuate the switch when the iron lies flat on the soleplate without movement for a first predetermined period of time.
 3. The apparatus of claim 2 wherein the first predetermined period of time is from about thirty seconds to about sixty seconds.
 4. The apparatus of claim 1 further comprising an attitude detector and wherein the auto-shutoff circuit is adapted to actuate the switch when the iron is upright without movement for a second predetermined period of time.
 5. The apparatus of claim 4 wherein the first predetermined period of time is from about fifteen minutes to about thirty minutes.
 6. The apparatus of claim 1 further comprising a light source indicating when power is being supplied to the soleplate heater.
 7. The apparatus of claim 6 wherein the light source is integrated into the switch.
 8. The apparatus of claim 1 wherein the auto-shutoff circuit comprises a timer.
 9. The apparatus of claim 8 wherein the timer automatically resets itself upon a change in the output of the motion sensor.
 10. The apparatus of claim 1 wherein the motion detector comprises a rolling ball switch.
 11. The apparatus of claim 1 wherein the motion detector comprises an inductive rolling ball switch.
 12. A pop-up auto-shutoff indicator for a pressing iron having a soleplate heater, comprising: a signal-activated pop-up switch adapted to provide power to the soleplate heater when depressed by the user; motion detector means for detecting movement of the iron; and auto-shutoff circuit means for receiving input from the motion detector means, providing a signal to de-activate the pop-up switch upon detecting no motion of the iron for a predetermined period of time and to disconnect power to the soleplate heater.
 13. A pop-up auto-shutoff indicator for a pressing iron having a soleplate heater, comprising: an electric signal-activated pop-up switch adapted to provide power to the soleplate heater and to one or more DC power supplies when depressed by the user; a pop-up switch signaling device adapted to signal the pop-up switch; and an interface to provide to a controller control over the signaling device, so as to enable the controller to activate the pop-up switch.
 14. A user-actuated electromechanical switch assembly for providing power to an iron, comprising: a movable switch having an on position and an off position, said on and off positions being visible by a user; and a motion detector adapted to actuate said switch.
 15. A mechanical auto-shutoff indicator for a pressing iron, comprising: a signal-activated electromechanical switch assembly having a moveable element and adapted to provide power to the iron when the moveable element is moved from an open circuit position to a closed circuit position by the user; a motion sensor; and an auto-shutoff circuit adapted to receive input from the motion detector and provide a signal to activate the electromechanical switch assembly upon detecting no motion of the iron for a predetermined period of time; wherein activation of the electromechanical switch assembly causes the moveable element to move to the open circuit position; and wherein the open-circuit position of the moveable element is visible to the user.
 16. The indicator of claim 15, wherein the indicator projects outwardly from the iron in the open-circuit position. 